Apparatus for drawing hollow blanks



June 24, 1930. HEETKAMP 1,767,845

APPARATUS Fo'a DRAWING HOLLOW BLANKS- Filed May 25, 1928 fizz/9%: HemrLclL Heat/whip,

Patented June 24, 1930 UNITED STATES PATENT OFFICE summon nnnrxmze, or mnsnone, GERMANY, ASSIGNOR 'ro DEMAG AK'I'IEN en- SELLSCHAFT, or norsnoae, PRUSSIA, GERMANY, A sroox COMPANY, or rnossra,

GERMANY APPARATUS FOR DRAWING HOLLOW BLANKS Application filed May 25, 1928. Serial No. 280,476, and in Germany May 31, 1927.

This invention relates to a new and improved apparatus for drawing hollow blanks and more particularly to a. construction of such apparatus whereby the mandrel is supported when withdrawn from the drawing dies.

In the drawing of hollow blanks it is customary to pierce the piece being worked upon, place it upon the end of'a lon mandrel and force the mandrel and wor -piece through a series of drawing dies which progressively reduce and elongate the workpiece to form the seamless tubing. The mandrelconsists of a long rod which is permanently supported only at its end most distant from the drawing dies. When it is passed into the drawing dies it is supported by the contact of the work-piece with the drawing dies. When it is withdrawn from the drawing dies it is not supported in normal constructions except at one end.

It will be apparent that there is considerable tendency for the mandrel to bend and sag, especially when the weight of the work-piece is -"placedupon. the free end. Even if supported by rollers or thelike adjacent the free end, there is a tendency for the mandrel to sag in the middle, causing its end to incline upwardly. It will be apparent that-in order to form tubing having uniform wall thickness throughout its circumference it is essential that the mandrel be exactly centered in relation to the drawing dies, and maintained centered and without lateral thrust throughout its range of movement.

It is an object of the present invention to provide apparatus of this character having means supporting the mandrel when clear of the drawing dies.

It is another object of my invention to provide such a construction in which the supports are withdrawn from the mandrel as it enters the drawing dies and in which the supports are moved into contact with the mandrel as it is withdrawn from the drawing dies.

It is also an object to provide construction of this character in which the move- Figure 3 is a transverse section taken on the line 3-3 of Figure 1; and

Figure 4 is a transverse section taken on the line 4-4 of Fi re 1, but with the mandrel moved to the aft.-

. The apparatus comprises the draw bench bed 1, upon which is slidably supported the carriage 2. The left-hand portion 2 of the bed 1 carries the consecutively arranged drawing dies 3. These dies 3, as shown in the drawings, are progressively reduced in size toward the left end of the apparatus. The carriage 2 is provided upon its lower surface with the rack 15 which meshes with the gear 6'. This gear serves to move the carriage back and forth and may be driven ,by any suitable source of power (not shown).

The mandrel bar 5 is supported at .its right-hand by the thrust member 6, carried by the carriage 2. The work-piece 4 is shown placed upon the end of the mandrel 5.

The su porting arms 8 are pivotally secured at g to the upper portion of the car riage 2, as best shown in Figures 3 and 4. These arms 8 are provided with the rollers 9. These rollers 9 run upon the rails 11, which rails may be laterally adjusted upon their supports 10 by means of the hand wheels 12. The rails 11 are provided with downwardly inclined portions 14 so that the rollers 9 pass down these inclined portions and rest upon the upper surface of the bed 1 when the mandrel is introduced into the drawing dies. This position of the arms and rollers is clearly shown in Figure 1. The arms 8 are provided with extensions so that they enclose and support the mandrel 5, as clearly shown in Figure 3. By lateral adjustment of the rails by means of the hand wheels 12, the position of the arms 8, and consequently of the mandrel, may be accurately determined.

In the operation of the apparatus the parts will be in the position shown in Figures 1 andv 2 and the work-piece will be applied thereto. The gear 6' is then rotated in the counter-clockwise direction which moves the carriage 2 and mandrel 5 to the left. The work-piece is forced through the series of drawing dies 3 and is progressively reduced in size.- As the rollers 9 of the first pair of supporting arms 8 reach the downwardly inclined track portions 14 these arms swing apart by gravity and swing clear of the drawing dies, as clearly shown in Figure 4, so that the carriage may pass under the drawing dies, while the mandrel passes through the drawing dies.

After completing the forming stroke, the direction of rotation of the gear 6 is reversed andthe carriage moves to the right. As the wheels 9 of each pair of arms 8 reach the inclined track 14, the arms are swung upwardly and the mandrel again gripped and supported.

While I have shown one preferred form of construction by way of illustration, it will be apparent that my invention may be embodied in other forms with the movable supports and other, operating means designed in other ways and it is to be understood that I contemplate such chan es and modifications as come within the spirit and scope of the appended claims.

I claim:

1. Apparatus for drawing hollow blanks comprising a supporting bed, drawing dies supported on said bed, a mandrel permanently supported at one end, means for moving the mandrel longitudinally throu h the drawing dies, supports for the mandre movable longitudinally with the mandrel and movable relative to the mandrel, and meansfor permitting movement of the supports relative to the mandrel as the mandrel passes into the drawing dies.

2. Apparatus for drawing hollow blanks comprising a supporting bed, drawing dies supported on said bed, a mandrel permanently supported at one end, means for moving the mandrel longitudinally through the drawing dies, a plurality of'spaced supports engaging the mandrel when clear of the drawing dies, said supports moving longitudinally with the mandrel and means progressively causing the withdrawal of said supports as the mandrel enters the drawing dies.

3. Apparatus for drawing hollow blanks comprising a supporting bed, drawing dies supported on said bed, a mandrel permanently supported at one end, means for moving the mandrel longitudinally. through thee- 7' drawing dies, a plurality of swinging sup ports movable longitudinally with the mandrel and engaging the mandrel when clear longitudinally of the bed, a mandrel permanently supported at one-end from the carriage and supports for the mandrel mounted on the carriage movable toward and from the mandrel. I

5. Apparatus for drawing hollow blanks comprising a' supporting bed, drawing dies supported by said bed, a carriage movable longitudinally of the bed, a mandrel permanently supported at one end from the carriage, movable supports for the mandrel carried by the carriage, andmeans causing the withdrawal of said movable supports from contact with the mandrel as the mandrel enters the drawing dies.

6. Apparatus for drawing. hollow blanks comprising a supporting bed, drawing dies supported by said bed, a carriage movable longitudinally of the bed, a mandrel permanently supported at one end from the carriage, movable supports for the mandrel carried by the carriage, and guide members causing the movable supports to engage the mandrel as it emerges from the drawing dies.

v 7. Apparatus for drawing hollow blanks comprising a supporting bed, drawing dies supported by said bed, a carriage movable longitudinally of the bed, a mandrel permanently supported at one end from the carriage, swinging mandrel supports pivoted to the carriage and guide rails engag ing the swinging supports to permit the supports to swing clear of the mandrel as it enters the drawing dies and to cause the supports to engage the mandrel as it emerges from the drawin dies.

8. Apparatus or drawing hollow'blanks, comprising a supporting bed, drawing dies supported by said bed, a carriage movable longitudinally of the bed, a mandrel supported at one end by the carriage and extending above the carriage, swinging supports carried by the carriage and adapted to engage opposite sides of the mandrel, and means to swing the supports into engagement with the mandrel.

9. Apparatus for drawing hollow blanks, comprising a supporting bed, drawing dies supported by said bed, a carriage movable longitudinally of the bed, a mandrel sup ported at one end by the carriage and extending above the. carriage, swinging supports carried by the carriage and adapted to engage opposite sides of the mandrel, the

arms beingpivoted to the foarriage upon a common axis located below the mandrel, and means to swing the supports into engagement with the mandrel.

10. Apparatus for drawing hollow blanks, comprising a supporting bed, drawing dies supported by said bed, a carriage movable longitudinally of the bed, a mandrel supported at one end by the carriage and extending above the carriage, swin in sup- "ports carried by the carriage an a apted to engage opposite sides of the mandrel, and guide rails carried by the supporting bed adapted to swing the arms against the mandrel at points clear of the draw rings.

11. Apparatus for drawing hollow blanks, comprising a supporting bed, drawing dies supported by said bed, a carriage movable, longitudinally of the bed, a mandrel supported at one end by the carriage and extending above the carriage, swin 'ng supports carried by the carnage an adapted to engage opposite sides of the mandrel, guide rails carried by the supporting bed adapted to swing the arms agalnst the mandrel at oints clear of the drawin dies, and means fbr adjusting the guide rai s'laterally to modify the supported position of the mandrel.

a0 Signed at Cologne, Germany, this 11th day of May, 1928. g

- HEINRICH 'HEETKAMP. 

